Review web frameworks, build tools, and ML libraries to learn design patterns. Observe testing strategies, CI setups, and contribution practices.
Good repos have clear READMEs, active issue triage, and healthy release cadence. Start by building locally and running the test suite.
Focus on a smaller component or module. Document your understanding and propose improvements with minimal disruption.
Join community channels to understand roadmap and norms. Small, consistent contributions compound over time.